Some stray articles I found thinking of the recent warnings.
From Homeland1 and The Daily News Of Los Angeles, LA preparing for nuclear attack.
A couple years ago, from SfGate, Preparing for the unthinkable - nuclear attack.
Of course, we know that Al-Qaeda (whatever, whoever that is) is 'certain' to attempt to attack us in the next six months from this Washington Post article.
With these kinds of choices, one almost wishes they would just stick to knocking down single buildings, and not mile radiuses of them, whoever "they" actually are.
Update: Fema has NLE exercises planned for nuclear detonation scenarios for May of 2010 in Regions IX (CA,NV,AZ) and VIII (MT,WY,UT,CO,ND,SD) and the NCR, or National Capitol Region, as well as continuity of government scenarios under the name Eagle Horizon.